Pulp used to form paper contains a number of impurities which tend to deposit on the paper making equipment. One such impurity is “pitch” which refers to deposits originating from natural resins and their salts. Stickies is a term that refers to hydrophobic components used in the manufacture of a paper product. Stickies arise from residues of polymers that are used in retention aids, drainage aids, adhesives, ink resins and coatings used in various processes of making paper. The term “stickies” has increasingly been used to describe deposits that occur in systems using recycled fiber.
Although paper manufacturers go to great lengths to prevent pitch and sticky deposits on the paper making equipment as well as the deposition of other unwanted material such as dirt, grime and the like, eventually the equipment must be cleaned.
Current commercial cleaners generally are very alkaline and/or chlorine-containing (i.e., chlorine bleaches) chemical compositions. They can be used in a variety of different manners including a boil-out procedure where the hot cleaning solution is circulated through the paper making equipment, or can be sprayed directly onto equipment.
With either type of solution, worker safety is an issue. Further, waste disposal is a problem. The highly caustic material must be neutralized prior to disposal. This requires highly acidic mineral acids and presents additional safety concerns. Chlorine-containing compositions present additional environmental concerns.